.box {
    overflow: hidden;
    background-color: white;
}

header {
    background-color: white;
    height: 1.6rem;
    min-width: 320px;
    max-width: 740px;
    overflow: hidden;
    position: fixed;
    width: 100%;
    display: flex;
    align-items: center;
    border-bottom: 1px solid #cccccc;
    display: flex;
}

header .back-btn {
    box-sizing: border-box;
    /* border: 1px solid red; */
    margin-bottom: .1rem;
    width: 5%;
    flex: 1;
    text-align: center;
}

.back-btn img {
    width: 100%;

}

.header-search {
    height: 1.3rem;
    /* border: 1px solid red; */
    font-size: .5rem;
    width: 95%;
}

.s-in {
    height: 100%;
    width: 85%;
    margin: 0 1% 0 3%;
    border: none;
    background-color: rgb(238, 236, 236);
    border-radius: .5rem;
    padding-left: .6rem;
}


/* =====2、导航栏======= */
nav {
    margin-top: 45px;
    width: 15%;
    float: left;
    background-color: rgb(250, 248, 245);
    margin-bottom: 2.5rem;
    /* 添加滚动条 */
    overflow: auto;
    position: fixed;


    /* border: 1px solid red; */
}

nav a {
    display: block;
    font-size: .6rem;
    margin: 0;
    padding: 5px;
    white-space: nowrap;
    width: 100%;
    overflow: hidden;
    text-overflow: ellipsis;
    text-align: center;
    line-height: 45px;
}

/* ======主体内容区域========== */
.main-contain {
    /* overflow: auto;  添加滚动条 */
    margin-top: 50px;
    margin-bottom: 2.5rem;
    width: 85%;
    float: right;
}

.main-contain ul {
    display: flex;
    flex-wrap: wrap;
}

.main-contain ul li {
    text-align: center;
    width: 33%;
    /* border: 1px solid red; */

}

.main-img {
    display: inline-block;
    text-align: center;
    width: 80%;
    /* border: 1px solid red; */
}

.main-contain img {
    width: 100%;
}

.main-contain ul li span {
    font-size: .5rem;
    display: block;
    margin-top: 3%;
    margin-bottom: 10%;
    /* border: 1px solid red; */
}

.main-header {
    /* border: 1px solid red; */
    overflow: hidden;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;

}

.main-header .header-title {
    padding: 5px;
    font-size: 1rem;
    font-weight: 700;
}

.main-header a {
    width: 20%;
    text-align: center;
    /* border: 1px red solid; */
    display: flex;
    align-items: center;
}

.main-header a i {
    /* background-color: pink; */
    width: 20%;
}

.main-header a i img {
    width: 100%;
    padding-bottom: 3px;
}

.main-header a i:nth-child(1) {
    margin-right: 5px;
}

.main-header a div {
    font-size: .5rem;
}

/* ======底部用户操作区域=========== */